Speed-varying device for machine-tools.



W. C. FISH.

SPEED VABYING DEVICE FOR MACHINE TQOLS.

. APPLICATION FILED APR.2, 1903. 1,008,593.

Patented Nov. 14, 1911.

lnvenfior:

Witnesses:

' UNITED STATES PATENT oFFroE.

WALTERC. FISH, 0F LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COM-PAN' Y, A CORPORATION OF NEW YORK.

SPEED-VARYIIIG DEVICE FOR MACHINE-TOOLS Specification of Letters Patent.Patented Nov. 14 1911 Application filed April 2, 1903.

Serial No. 150,710.

To all whom it may concern:

Be it known that I, WALTER C. FISH, a citizen of the United. States,residing at Lynn, county of Essex, State of. Massachusetts, haveinvented certain new and useful Improvements in Speed-Varying Devicesfor Machine-Tools, of whichthe following is a specification.

This invention relates to machine tools, and its object is to providemeans for varying the speed of the machine in accordance with the workbeing done by the cuttingtool.

In operating planers, milling machines, shaping machines, and the like,the relative movement of the cuttingtool and the work is usually at thesame rate of speed during the entire working travel or stroke. On thereturn stroke, the movement is usually more rapid, as no work is beingdone. But in many jobs there are portions below the level at which,..thetool is cutting which do not require to be operated on, and yet the toolmust travel idly over these portions at the normal slow cutting speed.This involves considerable .loss of time, and the object of my inventionis to cause the tool to move quickly over such'idle spots but resume itsnormal speed when it'reaches a portion on which it is to take a out.

Many diiferent ways may be devised for carrying out my invention. Iprefer to drive the machine tool by means of an electric motor, and toprovide for the reversal of the motor when the stroke of the bed or thecutting tool is to be reversed. I also provide means for varying thevoltage of the current supplied to said motor, in accordance with thecutting periods and idle periods of the tool so that the motor will runat a moderate speed when the tool is taking a cut, and at a higher speedwhen the tool is passing idly over portions below its level. I prefer touse a reversible tool, so that it will cut on each stroke of the bed orporter-bar, and in this case the currentacontroller must be capable ofreverse action on the return stroke,

all as hereinafter set forth and particularly pointed out in the claims.9 I

the current-controlling switch; Fig. 5 is a top plan view of thereversing switch; Fig. 6 is a diagram of the circuits. 1

The invention is applicable to a large variety of metal-working andwood-working machines, but for convenience I have shown it applied to. ametal planer having a frame 1, an adjustable tool-carriage 2, areciprocating work-table or bed 3, and an electric motor 4 for movingsaid bed and operating the tool-feeding devices, the latter being notshown to avoid complicating the drawing. The ciitting-tool 5 ispreferably mounted in a rotatable holder 6, so that it can be reversedat the end of each stroke of the bed and will thus out both ways. Suchtoolholders have been heretofore patented and form no part of myinvention. See for example,' the patent to Paine, No. 119,395,

Sept. 26, 1871.

The direction of rotation of the motor is controlled by a reverser 7whose handle 8 is moved one way or the other by dogs 9 securedadjustably to the reciprocating bed 3 at points just beyond the ends ofthe piece which is being planed. This piece of work is represented ashaving high portions 10 on which a. cut is taken, and low portions 11over which the tool passes idly.

The motor is supplied with current from a positive main 12 through oneor' the other of two branch leads 13, 14, the former'including anon-inductive resistance 15. A double-pole switch 16 connects the main12 with the leads 13, 14. A switch 17 connects one' or the other ofthese leads with one terminal of the motor, the other motor terminalbeing connected by switch 16 directly with Y the negative main 18; Thereversing. switch 7 is interposed between the switch 17 and the motor.When the lead 13 is in circuit, the motor runs slowly, and when the lead14' is out in, the motor speeds up.

In order to shift the switch 17 a'utomatically at the proper time, thebed of the planer carries cams to actuate said switch. These arepreferably constructed and arranged. as follows: A rod 19 extends alongthe side of the bed, being supported at each end in brackets 20 on saidbed. Slidably and rotatably. mounted on the rod are a plurality ofblocks 21, each having arounded lug or cam 22, and provided wlth one or-more setscrews 23, to enable it to be adjustably secured to the rod.The switch 17 has two legs 17, 17 which straddle the rod 19, the spacebetween the ends of s aid legs being just suificient to permit acam-block to pass through as shown in Fig. 4. As the bed moves along,the cams rock the switch on its ivot 24, and cause it to make contactalternately with the plates 25, 26, which form the terminals of'thebranch leads 13, 14. "A spring 27 gives the switch a snap action inpassing from one plate to the other by adjusting the cams to correspondwith the high and low portions of the work, the motor will be speeded upand slowed down accordingly. The cams are made rotatable on the rod sothat they can be set to throw .the switch up or down as desired.

The arrangement of cams which will make the proper speed changes whenthe bed moves in one direction will produce just the opposite effectwhen itmoves in the opposite direction. It is therefore necessary toreverse not only the motor, connections but the connections between theleads 13, 14,andthe .plates 25, 26, at each end of the stroke of thebed. This, is done by means of a reversing switch 28, and the tworeversing switches may be conveniently 'rouped in one structure. Fig. 6shows the evelopment of such a double reverser, the movablesegments-being shown by rectangles, and the stationary contact-fingersby circles. The movable segments are-in practice mounted on a rotatablecylinder 29,

which is oscillated by the dogs 9 at the end' of each stroke. By tracingout the circuits, in connection with the arrangement of cams in Fig.2,itwill be seen that the high portions of the work will move slowly underthe tool in both directions, and the low portions will move rapidly.Thus with the parts standing as shown, the bed is moving to the rightand the switch 17 he's been thrown onto the plate 25. The reverser is insuch position that the tier of segments marked a is supposed to be incontact with the fingers. Gui-dent will therefore flow through the lead13, the resistance 15, the finger 13, the connected segments 13*, 25*,the plate 25, switch 17, lead 30, finger 30, segments 30 and 31 finger31 and lead 31 to the motor. When the end of the cut on the high portion10 is reached, the upwardly projecting cam will shift the switch 17 tothe plate 26, and a current of higher voltage will-flow to the motorthrough the lead 14,

finger 14, segment 14*,plate 26, switch 17,

lead 30, finger30, segments 30, 31, finger 31' and lead 31. As. the bedreaches the endfo f its movement to the right the end cam throws theswitch 17 up to the plate 25 and the motor slows down just before it isreversed. As soon-as the reverser is moved to position b, the motorbegins running in the other direction and the bed begins its movement tothe left, the-tool aving been relead 14, finger 14, segments 14, 25",plate 25, lead 30, finger 30, segments 30 and 32 finger 32 and lead 32to the motor, which is thus caused to run rapidly until the tool reachesits out, when the second cam throws the switchover to the plate 26, andthe cir--- cuitis then via lead 13, resistance 15, finger 13, segments13 and '26", plate 26, to switch 17 and thence to lead 32 as before. benoted that for this position of the reverser, the motor runs slowly whenthe switch 17 is on plate 26, whereas in the first position it runsslowly when the switch is on plate 25. Many other schemes for carryingout my invention may be devised, and I do not wish to be understood aslimiting myself to the one hereinbefore described.

VVhatI claim as new, and desire to secure 1. The combination with aplaneror similar machine tool and its reciprocating driving'means, ofmeans for varying the speed of said driving means during movement in asingle direction corresponding to the out- It will by Letters Patent ofthe United. States, is,--

ting periods and idle periods of the cutting tool, and means forreversing the operation of said speed varying means upon reversal of thedirection of movement of the. machine.

2. The combination with a planer or similar machine tool adapted tooperate on both forward and return movements and its reciprocatingdriving means, of means for varying the speed of said driving meansduring movement in a single direction according to the cutting periodsand idle periods of the cutting tool, and means for reversing theoperation of said speed varying direction of movement of the machine.

3. The combination with a planer or similar reciprocating machine tooladapted to operate on both forward and return movements, of meanscomprising a movable mem- 4. The combination with a planer or simi-' larreciprocating machine tool adapted to operate on both forward and returnmovements, of means comprising a pivoted memher for var ing its speed,an operator therefor driven y the reciprocating machine tool andprovided with actuating surfaces for engaging said pivoted-member and sodisposed as to efiect an increaseof speed at the commencement of theidle periods and means simultaneously with the reversal of a decrease ofspeed at the commencement of the cutting periods of the cutting tool,

and means for reversing the operation of said speed changing means uponreversal of the machine.

5. The combination with a double acting planer, of means for varying itsspeed, a speed changin device having a movable actuating mem r, cams orprojections for controlling said actuating member carried by themovablemember of the laner, and means for reversing the effect 0? saidcams or projections upon the s vice on reversal of the 'rection ofmovement of said movable member.

6. The combination, with a machine tool,

' of an electric motor for driving it, a reversing switch for saidmotor, leads for supplying current of difierent voltages to said motor,a switch controlling said leads,

(1 changing demeans for automatically shiftin said controlling switch inaccordance wit the work, and a reversing switch for said leads.

7. The combination with a machine tool, of'an electric motor for drivingit, a reversing switch for said motor, leads for supplying current ofdifferent voltages to said motor, a switch controlling saidleads, meansfor automaticall shiftin said controlling switch in accor ance wit thework, a reversing switch for said leads, and means for operating saidreversing switches simultaneously.

In witness whereof I have hereunto set my hand this 30th day of March,1903.

DUGALD McK. MCKILLOP, J on)! A. MCMANUS.

